• Title/Summary/Keyword: Lead sulfide

Search Result 68, Processing Time 0.027 seconds

Direct Acid Leaching of Zinc from Marmatite Ores 3 Acid Leaching of Marmatite Ores and the Electrode Potential Behavior of Sulfides (Marmatite 鑛의 直接酸浸出에 關한 硏究 (第3報) Marmatite 鑛의 酸浸出과 黃化物의 電極電位에 關한 硏究)

  • Kim Jae Won
    • Journal of the Korean Chemical Society
    • /
    • v.11 no.1
    • /
    • pp.38-43
    • /
    • 1967
  • In order to explain the positive catalytic action of copper compound for the rate of leaching of zinc sulfide minerals, the electrode and redox potentials of both synthetic and natural sulfides were measured at various conditions of temperatures and pressures. The potentials of Chalcopyrite and copper sulfide were considerably higher than that of zinc sulfide, whereas lead sulfide and Galena had slightly lower potentials than that of zinc sulfide. At elevated temperatures and pressures, the same tendency was obtained. By means of comparing the calculated and measured values of potentials for sulfides, it was suggested that the electrode potentials in acid solution were generated by oxidation of sulfur ion. As a result, it was concluded that the catalytic action of copper compound in the leaching of synthetic zinc sulfide should be arised from the galvanic action between sulfides keeping intimate contact one another in which copper sulfide worked as cathodic and zinc sulfide as anodic part analogous to the metal corrosion under galvanic action.

  • PDF

Effect of Shock Wave Exposure on Structural, Optical and Magnetic Properties of Lead Sulfide Nanoparticles (충격파 유동노출에 따른 황화납 나노소재의 미세구조 및 자기광학적 특성 분석에 관한 실험적 연구)

  • Kiwon Kim;Surendhar Sakthivel;J. Sahadevan;P. Sivaprakash;Ikhyun Kim
    • Journal of the Korean Society of Visualization
    • /
    • v.22 no.1
    • /
    • pp.18-27
    • /
    • 2024
  • A series of shock wave pulses with Mach number 2.2 of 100, 200, and 300 shocks were applied to lead sulfide (PbS) nanomaterials at intervals of 5 sec per shock pulse. To investigate the crystallographic, electronic, and magnetic phase stabilities, powder X-ray diffractometry (XRD), diffused reflectance spectroscopy (DRS), and vibrating-sample magnetometry (VSM) were employed. The material exhibited a rock salt structure (NaCl-type structure); XRD results indicated that material is monoclinic with space group C121 (5). Further, XRD results showed shifts due to lattice contraction and expansion when material was subjected to shock wave pulses, indicating stable material structure. Based on the data obtained, we believe that the PbS material is a good choice for high-pressure, high-temperature, and aerospace applications due to its superior shock resistance characteristics.

A Molecular Biotechnology For Removal of Toxic Heavy Metals

  • Bang Sang-Weon;Clark Douglas S.;Keasling Jay D.
    • Proceedings of the Microbiological Society of Korea Conference
    • /
    • 2000.10a
    • /
    • pp.128-135
    • /
    • 2000
  • The thiosulfate reductase gene (PhsABC) from Salmonella typhimurium was expressed in Escherichia coli in order to produce sulfide from inorganic thiosulfate and precipitate metals as metal sulfide complexes. A 5.1-kb DNA fragment containing the native phsABC and a 3.7-kb DNA fragment, excluding putative promoter and regulatory regions were inserted into expression vectors pTrc99A and pJB866, respectively. Upon expression of phsABC, E. coli DH5$\alpha$ harboring the phsABC constructs showed higher thiosulfate reductase activity and produced significantly more sulfide than the control strain (E. coli DH5$\alpha$) under both aerobic and anaerobic conditions. Among the four constructs, E. coli DH5$\alpha$ harboring pSB74 produced the highest level of thiosulfate reductase and removed most of heavy metals from solution under anaerobic conditions. In a mixture of 100 $\mu$M each of cadmium, lead, and zinc, the strain could remove $99\%$ of the total metals from solution within 10 hours. Cadmium was removed first, lead second, and zinc last. In contrast, a negative control did not produce any measurable sulfide and removed very little metals from solution. These results have important implications for removal of metals from wastewater contaminated with several metals.

  • PDF

Polyester (PET) Fabric dyed with Lead (II) acetate-based Colorimetric Sensor for Detecting Hydrogen Sulfide (H2S) (황화수소(H2S) 감지를 위한 아세트산 납이 침염된 폴리에스터(PET) 섬유 기반의 변색성 센서)

  • Lee, Junyeop;Do, Nam Gon;Jeong, Dong Hyuk;Jung, Dong Geon;An, Hee Kyung;Kong, Seong Ho;Jung, Daewoong
    • Journal of Sensor Science and Technology
    • /
    • v.29 no.5
    • /
    • pp.360-364
    • /
    • 2020
  • In this study, the colorimetric sensor, polyester (PET) fabric dyed with lead (II) acetate (Pb(C2H3O2)2), was fabricated and characterized for the detection of the hydrogen sulfide (H2S). The surface morphology of the fabric was determined using scanning electron microscope and energy-dispersive X-ray spectroscopy. The optical properties of the fabric were evaluated by measuring the variation in the blue value of an RGB sensor. The fabric showed a significant color change, high linearity (R2 : 0.98256), and fast response time (< 1.0 s) when exposed to H2S. This is because the sensor is highly porous and permeable to the gas. The fabric can not only be used as a hydrogen sulfide sensor but also be used to detect and prevent H2S influx using sticky tape on pipelines.

A Study on the Pb-contaminated Soil Remediation by Organic Acid Washing (유기산을 이용한 납 오염토양의 복원에 관한 연구)

  • 정의덕
    • Journal of Environmental Science International
    • /
    • v.9 no.5
    • /
    • pp.437-441
    • /
    • 2000
  • A study on the removal of Pb ion from Pb-contaminated soil was carried out using ex-site extraction process. Tartaric acid (TA) and iminodiacetic acid sodium salt(IDA) as a washing agent were evaluated as a function of concentration reaction time mixing ratio of washing agent and recycling of washing agent. TA showed a better extraction performance than IDA. The optimum washing condition of TA and IDA were in the ratio of 1:15 and 1:20 between soil and acid solution during 1 hr reaction. The total concentrations of Pb ion by TA and IDA at three repeated extraction were 368.8 ppm and 267.5 ppm respectively. The recovery of Pb ion from washing solution was achieved by adding calcium hydroxide and sodium sulfide form the precipitation of lead hydroxide and lead sulfide and optimum amounts of sodium sulfide and calcium hydroxide were 7 g/$\ell$ for the TA washing solution and 4 g/$\ell$, 5g/$\ell$ for the IDA washing solution respectively. The efficiency of recycle for TA and IDA washing solution were 78.8% , 95.1%, and 89.2%, 96.6% at third extractions under $Na_2S$ and $Ca(OH)_2$, respectively.

  • PDF

Reduction Mechansim of Organophosphorus Compounds (유기인제의 수소 환원)

  • Lee Myung Yun
    • Journal of the Korean Chemical Society
    • /
    • v.13 no.2
    • /
    • pp.141-147
    • /
    • 1969
  • Organophosphorous compounds can be reduced by zinc metal in acidic solution after alkaline hydrolysis. Although phosphates and phosphonates did not evolve any gas, dithioates did evolve hydrogen sulfide and phosphine, thionates and thiolates did evolve only hydrogen sulfide. The evolved gases were qualitatively detected by means of lead acetate and silver nitrate or mercuric bromide papers and determined by spectrophotometrically. The reduction mechanism and analytical method of dithioates were proposed.

  • PDF

A study of the sulfide stress corrosion cracking characteristic of A106 Gr B steep pipe weldment (황화수소환경에서 A106 Gr-B 강 용접부의 응력부식균열 특성 평가)

  • Lee, Gyu-Young;Park, Kwang-Jin;Bae, Dong-Ho
    • Proceedings of the KSME Conference
    • /
    • 2007.05a
    • /
    • pp.114-119
    • /
    • 2007
  • Sulfide stress cracking (SSC) of materials exposed to oilfield environment containing hydrogen sulfide $(H_{2}S)$ has been recognized as a materials failure problem. Laboratory data and field experience have demonstrated that extremely low concentration of $H_{2}S$ may be sufficient to lead to SSC failure of susceptible materials. In some cases, $(H_{2}S)$ can act synergistically with chlorides to produce corrosion and cracking failures. SSC is a form of hydrogen embrittlement that occurs in high strength steels and in localized hard zones in weldment of susceptible materials. In the heat-affected zones adjacent to welds, there are often very narrow hard zones combined with regions of high residual stress that may become embrittled to such an extent by dissolved atomic hydrogen. On the base of understanding on sulfide stress cracking and its mechanism, SSC resistance for the several materials, those are ASTM A106 Gr B using in the oil industries, are evaluated.

  • PDF

Size Control of PbS Colloidal Quantum Dots and Their Application to Photovoltaic Devices

  • Lee, Wonseok;Ryu, Ilhwan;Choi, Geunpyo;Yim, Sanggyu
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2015.08a
    • /
    • pp.249.1-249.1
    • /
    • 2015
  • Quantum dots (QDs) are attracting growing attention for photovoltaic device applications because of their unique electronic, optical and physical properties. Lead sulfide (PbS) QDs are one of the most widely studied materials for the devices and known to have size-tunable properties. In this context, we investigated the relationship between the size of PbS QDs and two synthesizing conditions, a concentration of ligand, oleic acid in this work, and injection temperature. The inverted colloidal quantum dot solar cells based on the heterojunction of n-type zinc oxide layer and p-type PbS QDs were also fabricated. The size of the QDs and cell properties were observed to depend on both the QD synthesizing conditions, and hence the overall efficiency of the cell could vary even though the size of QDs used was same. The QD synthesizing conditions were finally optimized for the maximum cell efficiency.

  • PDF

Stability Assessment of Lead Sulfide Colloidal Quantum Dot Based Schottky Solar Cell

  • Song, Jung-Hoon;Kim, Jun-Kwan;An, Hye-Jin;Choi, Hye-Kyoung;Jeong, So-Hee
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2012.08a
    • /
    • pp.413-413
    • /
    • 2012
  • Lead sulfide (PbS) Colloidal quantum dots (CQDs) are promising material for the photovoltaic device due to its various outstanding properties such as tunable band-gap, solution processability, and infrared absorption. More importantly, PbS CQDs have large exciton Bohr radius of 20 nm due to the uniquely large dielectric constants that result in the strong quantum confinement. To exploit desirable properties in photovoltaic device, it is essential to fabricate a device exhibiting stable performance. Unfortunately, the performance of PbS NQDs based Schottky solar cell is considerably degraded according to the exposure in the air. The air-exposed degradation originates on the oxidation of interface between PbS NQDS layer and metal electrode. Therefore, it is necessary to enhance the stability of Schottky junction device by inserting a passivation layer. We investigate the effect of insertion of passivation layer on the performance of Schottky junction solar cells using PbS NQDs with band-gap of 1.3 eV. Schottky solar cell is the simple photovoltaic device with junction between semiconducting layer and metal electrode which a significant built-in-potential is established due to the workfunction difference between two materials. Although the device without passivation layer significantly degraded in several hours, considerable enhancement of stability can be obtained by inserting the very thin LiF layer (<1 nm) as a passivation layer. In this study, LiF layer is inserted between PbS NQDs layer and metal as an interface passivation layer. From the results, we can conclude that employment of very thin LiF layer is effective to enhance the stability of Schottky junction solar cells. We believe that this passivation layer is applicable not only to the PbS NQDs based solar cell, but also the various NQDs materials in order to enhance the stability of the device.

  • PDF

Benthic Fluxes of Ammonia and Lead in Lake Shihwa (시화호에서 암모니아와 납의 저층용출)

  • Han, Myong-Woo;Park, Yong-Chul;Huh, Sung-Hoi
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
    • /
    • v.2 no.2
    • /
    • pp.69-77
    • /
    • 1997
  • A 12-cm long sediment core was collected from a station in Lake Shihwa where high salinity-anoxic deep water is isolated from low salinity-oxic surface water by a strong halocline barrier. Unprecedented concentrations of porewater ammonia and lead are encountered: at 9 cm sediment depth ammonia builds up to 1420 ${\mu}M$ and at 3 cm lead to 1348 nM. As they are stable in anoxic condition, high concentrations of ammonia and lead suggest a development of notorious anoxic condition in the benthic environment of the lake. The degree of pollution of the deep water is likely to be directly proportional to the magnitude of benthic flux, because the deep water is isolated from the surface water by the halocline. Apparent coincidence of the ammonia residence time in the deep water with the elapsing time after the completion of the artificial lake construction, as about three years, suggests that the deep water pollution is being progressed entirely by benthic flux at least with respect to ammonia. The residence time for lead is such a short 20 days that it suggests a rapid return of the bottom water lead, which is originated from porewater by benthic flux, back to sediments probably as metal sulfide phases. The speculation on the return of lead as sulfide phases is likely to be supported by high concentration of hydrogen sulfide in the deep water and by high sinking rate of non-organic particles in Lake Shihwa.

  • PDF